### Answer --- Good point about cost optimization for voicemail messages in high-volume campaigns. Currently, the voicemail feature offers two options when a voicemail is detected: [(1) ]() 1. Static message — A pre-recorded message like

Hi, this is {{your name}}, please give us a callback tomorrow at 10am.

2. Prompt — A dynamically generated message based on instructions you provide (e.g.,

summarize the call and ask user to call back

) The static message option doesn't use an LLM at all, so for large volume campaigns where you want to minimize costs, using a static voicemail message would be the most cost-effective approach. For the prompt-based option, there isn't currently a documented way to specify a different/cheaper LLM specifically for voicemail message generation separate from the main agent's response engine. This sounds like a reasonable feature request — you may want to submit it directly to the Retell team via [Contact Sales]() or through [GitHub]() .

​ To learn more, see the sources I considered: [[1] Handle voicemail](https://docs.retellai.com/build/handle-voicemail) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

### Answer --- The available sources don't explicitly state whether static voicemail messages bypass LLM costs entirely. The documentation explains the two voicemail options: [(1) ]() - Static message — A pre-recorded message (e.g.,

Hi, this is {{your name}}, please give us a callback tomorrow at 10am.

) - Prompt — A dynamically generated message based on instructions you provide The billing documentation covers exceptions like minimum duration charges for dynamic opening messages and LLM price scaling for prompts exceeding 3,500 tokens, but doesn't specifically address voicemail LLM costs. [(2) ]() Logically, a static message wouldn't require LLM processing since it's pre-defined text, but I can't confirm this from the available sources. For a definitive answer on billing specifics, I'd recommend reaching out to: - [Contact Sales]() - [GitHub]() Would you like me to try answering this more generally based on my knowledge?

​ To learn more, see the sources I considered: [[1] Handle voicemail](https://docs.retellai.com/build/handle-voicemail) [[2] Exceptions to Our Per-Minute Pricing](https://docs.retellai.com/accounts/billing-exceptions) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.